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2011-07-03

HySpex hyperspectral scan of “The Scream” (1893).

The HySpex group at NEO is proud to announce that a very successful hyperspectral scan has been performed on Edvard Munch’s most famous painting “The Scream” (1893) at the National Museum in Oslo. The work was done in collaboration with Colorlab at Gjøvik University College and the conservation department at the National Museum.

The spectral reflectance of 416 wavelength bands throughout the visible, NIR and SWIR region (400nm to 2500nm) has been acquired using the HySpex VNIR-1600 and HySpex SWIR-320m-e instruments.

HySpex scanning of Edvard Munch's Scream

The SWIR-320m-e camera was operated in two different configurations, yielding a spatial resolution of¨0.29mm on the painting. The VNIR-1600 camera was configured to give a spatial resolution on the painting of ~0.2mm as well as an extraordinary 0.06mm (with full spectral resolution).

A two-axis computer-controlled translation stage has been integrated with the instrument software, enabling precise scanning of the camera and illumination source across the entire painting of size 91 x 73.5 cm.NEO has developed a special broadband light source, providing a line illumination with good uniformity and high intensity across the whole 400-2500nm range, which was gave a very good signal level. Custom designed polarizers were employed to avoid specular reflections from the painting surface.

Data from a large calibrated grey reflectance reference target and a Macbeth Colorchecker were also acquired as reference data for normalization and conversion to reflectance.

The sensitivity and speed of the instrument allowed scanning of a wide variety of configurations in just one day, including VNIR and SWIR scans at 1m as well as 30cm working distance, both with and without polarizers.The scan speed, ease of setup and configuration is essential in order for the technology to achieve more widespread use in museums and conservation labs.

This is probably the most detailed (spatially, spectrally and radiometrically) acquisition ever performed in the field of spectral analysis of cultural heritage objects in general and paintings in particular.

The setup is similar to the system that has been in operation at the C2RMF research lab at the Louvre Museum since 2010.

Several scientific publications and conference contributions are expected in the months ahead.